The tragic death of Heath Ledger and his incredible performance as the Joker led much of the coverage around Christopher Nolan’s Batman Begins follow-up, The Dark Knight. For Nolan, though, a driving force in the story was always Gotham’s unsung hero: the conflicted, but well-meaning city prosecutor, Harvey Dent. Nolan revealed that for him, the most fascinating storyline in the movie was Dent’s transformation into Two-Face.

“The way the story is constructed we always imagined that Harvey Dent would form the emotional arc of the story. His story, his tragedy would be, excuse me, the arc of the story, because The Joker, the purpose of The Joker for us was always that he has no arc, he has no development he doesn’t learn anything through the film, he’s an absolute.”

When the trailer for The Dark Knight debuted in theaters, the focus was on the incredibly captivating Heath Ledger in his psychotic joker makeup. Audiences were barely shown Harvey Dent, and his Mr. Hyde transformation into Two-Face was kept in secret for the most part. The onscreen version of Two-Face who audiences were familiar with was limited to the goofy version played by Tommy Lee Jones in 1995’s Batman Forever, a Two-Face that was probably a better fit for a carny than a Batman villain. The Dark Knight’s Two-Face, though, truly captured the horrifying portrayal of a man who suffered a gruesome injury. “When you look at Two-Face, you should get sick to your stomach,” Eckhart said.

When it was time to decide who would be the right fit, big shot names like Matt Damon were considered, but it was Aaron Eckhart’s work in several earlier films that convinced Christopher Nolan that he was the right man for the job. Nolan had first garnered an interest in Eckhart when casting the part of Leonard in Memento, but for whatever reason, Nolan said it wasn’t meant to be.

“I did meet with him about it and I was quite keen on him, but I don’t remember if he turned it down or whether we turned him down – it’s probably best if we both believe it our own way. But he was absolutely somebody that I was very, very interested in doing that role and I’d met with him about it. He’s always somebody that I’ve admired over the years and wanted to work with.”

In deciding where to find his Harvey Dent, Eckhart’s name again came to Nolan’s mind, primarily because of the characters he played just a few years earlier who veered off the straight path. Eckhart had displayed with three earlier films that he had a knack for portraying these multi-dimensional characters who didn’t have the boy scout morals they portrayed on the surface. A smooth-talking tobacco lobbyist in Thank You for Smoking, the cop headed on a path of destruction in The Black Dahlia, and a corporate employee with a malicious streak who toys with the emotions of a female coworker in The Company of Men. On the surface, they don’t come off as bad men, but peel back a few layers, and an uglier face is revealed.